R/rmAll.R

In svannoy/lsr-package: Companion Package to "Learning Statistics with R"

# file:    rmAll.R 
# author:  Dan Navarro
# contact: daniel.navarro@adelaide.edu.au
# changed: 29 June 2013

# rmAll() removes all variables from the workspace. It's not noticeably
# different to rm( list=objects() ), and it's largely unnecessary in
# RStudio because there's a button you can click to do the same thing,
# but it can be handy for beginners who don't yet understand how arguments
# work.
rmAll <- function(ask = TRUE) {
  
  # preliminaries
  env <- parent.frame() # evaluate in the parent frame
  object.list <- objects(env) # and the list of objects
  
  
  # ask the user if they mean it... 
  if ( ask ) {
    
    # don't bother if already empty
    if (length(object.list) == 0) {
      print("Workspace is already empty")
      return( invisible(1) )
    } 
    
    # first, display all the objects...
    cat("Current contents of workspace:\n")
    print( object.list )
    
    # then ask user for a decision...
    full.prompt <- paste( "Remove all objects? [y/n] ",sep = " ")
    response <- NA
    while( !(response %in% c("y","n")) ) {
      response <- readline( full.prompt )
    } 
    
    # bail out if necessary
    if( response == "n" ) { 
      return( invisible(0) ) 
    }
    
  }
  
  # remove everything and return
  rm( list = object.list, envir = env ) # ... remove all objects
  return( invisible(1) ) # ... return with invisible flag
  
}